#include<bits/stdc++.h>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
char cuv[10001];
int nrcuv,car;
char alfabet[]="abcdefghijklmnopqrstuvwxyzABCDEFIJKLMNOPQRSTUVWXYZ";
void prelucrare(char cuv[])
{for(int i=0;i<strlen(cuv);i++)
{if(strchr(alfabet,cuv[i]))
{nrcuv++;car++;
while(strchr(alfabet,cuv[i+1])&&i<strlen(cuv))
car++,i++;
}
if(strchr(alfabet,cuv[i])==0)
while(strchr(alfabet,cuv[i+1])==0&&i<strlen(cuv))
i++;
}
}
int main()
{while(f.get(cuv,10000))
prelucrare(cuv);
g<<car/nrcuv;
f.close();
g.close();
return 0;
}